System for integrating multiple chemical sensor data to detect an unmeasured compound

ABSTRACT

Methods for determining the presence of an unmeasured chemical in an environment can include receiving a plurality of sensor readings from a plurality of chemical sensors, wherein each chemical sensor of the plurality of chemical sensors is configured to detect a different chemical, determining a cross-sensitivity pattern from one or more unmeasured chemicals in the plurality of sensor readings, comparing the cross-sensitivity pattern with one or more known chemical patterns, determining that the cross-sensitivity pattern matches at least one of the one or more known chemical patterns that correspond to one or more chemicals, and identifying one or more unmeasured chemicals based on determining that the cross-sensitivity pattern matches the at least one of the one or more known chemical patterns.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 62/155,040 filed on Apr. 30, 2015 and entitled “System forIntegrating Multiple Chemical Sensor Data to Detect an UnmeasuredCompound.” This application also claims priority to Indian ProvisionalPatent Application No. 2186/CHE/2015 filed on Apr. 29, 2015 with theIntellectual Property Office of India and entitled “System forIntegrating Multiple Chemical Sensor Data to Detect an UnmeasuredCompound,” wherein both U.S. Provisional Patent Application Ser. No.62/155,040 and Indian Provisional Patent Application No. 2186/CHE/2015are incorporated herein by reference in their entirety.

BACKGROUND

Various systems exist to allow for the detection of compounds in anenvironment. Various sensor designs exist, and these sensors can he usedto detect the presence of a compound. However, in some industrialsettings a large number of chemical compounds can be present. Thedetection of all of these compounds may require a large number ofsensors across a relatively large area. Even if some compounds do notneed to be monitored, they may interfere with sensors designed tomonitor various compounds of interest. In some cases, misidentificationof a measured value can result due to the interfering effects of a gasthat is not being directly measured, which can lead to false alarmswithin a facility. The resulting system to monitor a region can becomplex, expensive, and prone to misidentifications and false alarms.

SUMMARY

In an embodiment, a method of determining the presence of an unmeasuredchemical in an environment can include receiving a plurality of sensorreadings from a plurality of chemical sensors, wherein each chemicalsensor of the plurality of chemical sensors is configured to detect adifferent chemical, determining a cross-sensitivity pattern from one ormore unmeasured chemicals in the plurality of sensor readings, comparingthe cross-sensitivity pattern with one or more known chemical patterns,determining that the cross-sensitivity pattern matches at least one ofthe one or more known chemical patterns that correspond to one or morechemicals, and identifying one or more unmeasured chemicals based ondetermining that the cross-sensitivity pattern matches the at least oneof the one or more known chemical patterns.

In an embodiment, a chemical compound measurement system comprises amemory storing an exposure application, a pattern store storing knownchemical patterns, and a processor. The exposure application, whenexecuted on the processor, configures the processor to: receive aplurality of sensor readings from a plurality of chemical sensors, whereeach chemical sensor of the plurality of chemical sensors is configuredto detect a different chemical, determine a cross-sensitivity patternfrom one or more unmeasured chemicals in the plurality of sensorreadings, compare the cross-sensitivity pattern with one or more of theknown chemical patterns, determining that the cross-sensitivity patternmatches at least one of the one or more known chemical patterns, wherethe one or more known chemical patterns correspond to one or morechemicals, and identifying one or more unmeasured chemicals based ondetermining that the cross-sensitivity pattern matches the at least oneof the one or more known chemical patterns.

In an embodiment, a method of determining the presence of a compound inan environment comprises receiving a plurality of sensor outputs from aplurality of chemical sensors, determining a cross-sensitivity patternresulting from the presence of the unmeasured compound using theplurality of sensor outputs, comparing the cross-sensitivity patternwith one or more known chemical patterns, determining that thecross-sensitivity pattern matches at least one of the one or more knownchemical patterns, wherein the one or more known chemical patternscorrespond to one or more compounds, and identifying the unmeasuredcompound based on determining that the cross-sensitivity pattern matchesthe at least one of the one or more known chemical patterns. Eachchemical sensor of the plurality of chemical sensors is configured todetect a different chemical, and a ratio of a first portion of each ofthe sensor outputs resulting from a detected compound to a secondportion of the sensor output resulting from an unmeasured compound is atleast about 2:1.

Embodiments described herein comprise a combination of features andcharacteristics intended to address various shortcomings associated withcertain prior devices, systems, and methods. The foregoing has outlinedrather broadly the features and technical characteristics of thedisclosed embodiments in order that the detailed description thatfollows may be better understood. The various characteristics andfeatures described above, as well as others, will be readily apparent tothose skilled in the art upon reading the following detaileddescription, and by referring to the accompanying drawings. It should beappreciated that the conception and the specific embodiments disclosedmay be readily utilized as a basis for modifying or designing otherstructures for carrying out the same purposes as the disclosedembodiments. It should also be realized that such equivalentconstructions do not depart from the spirit and scope of the principlesdisclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and theadvantages thereof, reference is now made to the following briefdescription, taken in connection with the accompanying drawings anddetailed description, wherein like reference numerals represent likeparts.

FIG. 1 schematically illustrates a sensor system for detecting one ormore chemical compounds in an environment according to an embodimentdisclosed herein.

FIG. 2 schematically illustrates a computer that can be used to carryout various steps according to an embodiment.

DETAILED DESCRIPTION

It should be understood at the outset that although illustrativeimplementations of one or more embodiments are illustrated below, thedisclosed devices, systems and methods may be implemented using anynumber of techniques, whether currently known or not yet in existence,The disclosure should in no way be limited to the illustrativeimplementations, drawings, and techniques illustrated below, but may bemodified within the scope of the appended claims along with their fullscope of equivalents.

In an embodiment, a workplace safety system may allow a plurality ofsensors associated with environmental, location, movement, and biometricinformation to be used to provide an integrated safety solution for oneor more workers. A number of sensors can be employed, and the data fromthe sensors can be combined to provide a better view of the personalsafety of the workers. For example, data from fixed and/or mobilesensors can be used to detect chemical components of an environment,environmental conditions (e.g., temperature, pressure, wind speed, winddirection, etc.), vibration levels, noise levels, biometric parameters(e.g., heart rate, body temperature, respiration rate, etc.), location(e.g., including 2-dimensional and/or 3-dimensional position), and thelike. The resulting data can be relayed through a communication moduleto a server, where the data can be combined to provide an overall viewof a workers risk factor. Various information such as alarms,notifications, information (e.g., maintenance protocols, instructions,live help, etc.), and the like can be relayed back to the worker throughthe system. The system may provide for better personal safety as aresult of real time or near real time updates, improved productivitythrough the processing of multiple types of data, and better workercompliance with safely protocols by providing real time or near realtime monitoring of personal protective equipment use, qualifications,and training for a variety of activities. All of these systems providefeedback to the worker to improve productivity, compliance, and safetyin ways that have not previously been as efficient.

In a first example, a plurality of chemical sensors can be used todetect a plurality of compounds in an environment. The resultingmeasurements can be used to identify a cross-sensitivity (e.g., aninterference caused in the measurement of a desired chemical by adifferent chemical present in the environment being detected by thesensor) from one or more of the sensors and matched to a set ofpatterns. The resulting pattern matching process can be used to identifya chemical in the environment that is not directly measured. Thespecific cross-sensitivity for each type of chemical sensor may providefor representative patterns that are specific to an unmeasured compound.In this way, the cross-sensitivity of a given chemical component for agiven set of chemical sensors can be thought of as having a fingerprintthat can be matched to a database of chemical fingerprints to identifythe compound. The resulting identification of the unmeasured compoundmay provide not only an identification of the chemical, but also ameasure of the chemical concentration in the ambient atmosphere. Theresulting identification of the chemical and its concentration can beused to eliminate the cross-sensitivity from the measured compounds. Thedetermined concentration can also be compared to an exposure thresholdto provide a level of safety with respect to the chemical, even when asensor is not present that directly detects the chemical. This mayextend the detection range of a multi-sensor array as well as reducingthe need for specialty chemical sensors in certain situations.

A feedback and learning mechanism can be used to indicate the presenceof the chemical and its fingerprint among other chemicals. This mayprovide an updated database of chemical fingerprints for use indifferent environments. The fingerprints or patterns can be distributedto a multi-sensor array to allow for real time or near real lime sensingof the detected chemicals as well as the undetected chemicals. Further,the correlation between sensor arrays in a facility may provide forimproved detection and mapping of each chemical within the facility.This system may use multiple sensor inputs to provide an indication ofunmeasured components to improve the safety of workers in a facility.

The determined chemical identity and concentrations can be used, aloneor in combination with other determined and/or measured compounds tocreate a mapping of the chemical concentrations in a facility. Themapping of a facility can be performed when sufficient spatialinformation is available, and a worker can proactively be warned not toenter certain areas based on the combined effects of the exposure tochemicals. The type of equipment used by the worker can be taken intoaccount in this analysis. In some embodiments, the system may suggestthe appropriate equipment, which may be more than the standard safetyequipment. This personal recommendation may increase the workersproductivity by avoiding having the worker return to a safety area toexchange their equipment during the performance of a job.

Referring to FIG. 1, a system 100 for providing workplace safety basedon a combination of sensor inputs is illustrated. As shown in FIG. 1,the system may comprise a plurality of sensors 152, 154 in signalcommunication with a communication node such as a safety communicator150. The safety communicator 150 may provide a data connection to a dataanalytics server 102 and/or a database 120 through a network 160. Thesafety communicator 150 may be wirelessly coupled to the network throughan access point such as a wireless fidelity (Wi-Fi), Bluetooth, orcellular connection (e.g., through a wireless service tower 164). Insome embodiments, the sensors can be in signal communication with awired communication node such as a router or other device that cancommunicate with the data analytics server 102 and/or a database 120through a network 160.

In the system 100, the network 160 may be the internet representing aworldwide collection of networks and gateways that use the TransmissionControl Protocol/Internet Protocol (TCP/IP) suite or protocols tocommunicate with one another. In some embodiments, the system 100 mayalso be implemented as a number of different types of networks such as,for example, an intranet, a local area network (LAN), or a wide areanetwork (WAN). FIG. 1 is intended as art example and not as anarchitectural limitation for varying embodiments.

The data analytics server 102 can comprise a memory 104, a processor106, and one or more applications 110 stored in the memory that canconfigure the processor 106 to perform certain functions. In general,the data analytics server 102 is configured to receive sensor data suchas indications of ambient chemical concentrations (e.g., current levels,voltage levels, calculated concentrations, etc.), biometric data,environmental data, and/or location data associated with a worker and/orone or more sensors and process the data to provide information to theworker and/or decision makers at a facility. The data analytics server102 is in communication with a database 120 that serves to storeinformation used within the system 100. The database 120 can include achemical pattern data store 122, a sensor calibration data store 124, ahistorical data store 126 and/or a personal protective equipment (PPE)data store 128.

The applications 110 can include an exposure application 112 and/or amanagement application 114. Each application can communicate with one ormore of the sensors 152, 154 and/or the safety communicator 150. Theexposure application 112 can receive the sensor data and perform patternmatching based on the plurality of chemical sensor measurements. Theresulting analysis can be used to detect one or more unmeasuredchemicals within a location (e.g., within one or more areas of afacility) and provide information to the safety communicator 150 and/orone or more sensors 152, 154. For example, the information can includealerts, notifications, information for performing a procedure, inputs(e.g., triggers, etc.) to safety devices, or the like.

In an embodiment, the exposure application 112 can receive a pluralityof inputs from the sensors. As described in more detail below, thesensors can measure ambient chemical concentrations, locationinformation, environmental information, biometric information from oneor more individuals, noise levels, and the like. The sensor data can bestored in the historical data store 126 and used with the system. Theexposure application 112 can use the sensor data along with the locationdata for the sensors to develop an exposure mapping of a facility forboth the detected chemicals and the one or more chemicals determined tobe present based on the multiple sensor inputs. For example, a model canbe used to predict the exposure at one or more locations within thefacility, and the prediction can include areas where sensors are notpresent. The exposure values can be determined for various environmentalhazards including chemical exposure, noise exposure, light and heatexposure and the like.

Once the exposure application 112 has determined exposure levels withina facility, the exposure values for a number of environmental hazardscan be combined to provide a better view of the personal safety of theworkers. For example, data for a chemical exposure at a given locationcan he used to determine and predict a potential chemical exposure atthat location. The sensor data can be stored in the sensor data store124 and accessed by the exposure application 112 along with the patterndata 122 as part of the determination of when one or more unmeasuredchemicals are present. The resulting measured sensor data and determinedchemical data can be stored in the historical data store 126. In someembodiments, the determination of the presence of an unmeasured chemicalcan be performed on the safety communicator rather than a back-endserver such as data analytics server 102.

The measurement and determination process can be repeated periodicallyby the exposure application 112. For example, the exposure applicationmay update the exposure values at an interval of less than one minute,less than five minutes, less than thirty minutes, or less than an hour.The rate at which the exposure values and/or the risk value rating areupdated may be based, at least in part, on the rate at which the sensordata (e.g., sensor values, location data, etc.) is updated andcommunicated back to the data analytics server 102.

In some embodiments, the exposure application 112 mar monitor theexposure value with respect to the location of one or more, individualsand provide feedback to a manager and/or the individuals based on theexposure value associated with the individual's location and/or expectedlocation based on predicted movements. The exposure value can bedetermined based on a base case for an individual without any PPE, or insome embodiments, an individual's PPE selection can be included in thedetermination of the exposure value. Using the plurality of sensorreadings (with or without the PPE considerations) to arrive at theexposure value may allow a worker's current exposure to be evaluated andcommunicated to each worker.

When a worker is at a location at which the exposure value exceeds athreshold, an alert, an alarm, a notification, and/or information (e.g.,maintenance protocols, instructions, live help, etc.), and the like canbe relayed back to the worker through the system. For example, the dataanalytics server 102 may send a message to the safety communicator 150to display the information. The alerts can indicate the level ofexposure, a notification that additional PPE is required, or anindication that the individual should not enter a specified area orleave an area if the individuals are already within the area. Theability to update the data and determine the exposure value in real timeor near real time may provide for better personal safety as a result ofreal time or near real time updates, improved productivity through theprocessing of multiple types of data, and better worker compliance withsafety protocols by providing real time or near real time monitoring ofpersonal protective equipment use, qualifications, and training for avariety of activities.

The safety communicator 150 may interact with one or more sensors toprovide the information to the system 100. The sensors can includesensors associated with an individual (e.g., a portable sensor) and/orfacility sensors (e.g., wireless or wired sensors including stationarysensors). In general, the individuals may wear one or more personalprotection equipment (PPE) devices for detection and communication. Forexample, a person may wear a portable chemical detector operable toidentify gases in the air and determine the levels of chemicals in theenvironment. The portable chemical sensor may comprise an array ofsensors to measure a plurality of chemicals. Also, a person may wear anynumber of monitoring devices that may monitor movement, breathing, heartrate, etc. Additionally, personnel may wear portable location devicesoperable to communicate the location of the device (and therefore theuser) to a central monitoring station. These portable devices maycommunicate wirelessly, over a wireless fidelity (Wi-Fi) network, viaBluetooth, or another wireless connection.

Facility sensors, which may be stationary within a facility, may also bepresent. The stationary sensors can measure any of the information thatthe portable and personal sensors can measure. The stationary sensorsmay also measure information such as environmental data (e.g., pressure,temperature, wind speed, wind direction, etc.). The facility sensors maycommunicate wirelessly and/or through a wired connection to the dataanalytics server 102 and/or the safety communicator 150 to provide dataused with the applications 110.

In some cases, the multiple PPE devices associated with an individualmay have alarms, notifications, or updates that are communicated to theuser via sounds, vibrations, or visual notifications. In someembodiments, each PPE device may communicate individually with thecentral monitoring station, employing multiple wireless infrastructures.In some embodiments, a safety communicator 150 (e.g., a communicationdevice) comprising a data collection and communication application maybe used to collect the sensor data and communicate the sensor data tothe various elements of the system 100. For example, the application mayestablish a connection between the smartphone and each of the PPEdevices, which may be wireless connections, such as Wi-Fi or Bluetooth.The application may then receive data from each of the PPE devices, andstore the data locally on the device. The application may also transferthe data to a cloud storage network via a cellular network.Additionally, the application may communicate the combined data from allof the PPE devices to the central monitoring station. The applicationmay automatically receive data from the PPE devices and send the data tothe data analytics server 102. Additionally, the application may beoperable to send messages or calls to other safely communicatorsassociated with other individuals if needed, such as in an alarm oremergency situation.

The application on the safety communicator 150 may present informationto the user via a user interface on the smartphone or connected to thesmartphone (such as a smartwatch). The interface may compile theinformation received from each of the PPE devices into a consistentformat, making it easier to read and understand. The user may be able toadjust alarm limits and settings in the application. The application mayshow real-time readings via the user interface, and may issue alerts orwarnings via the user interface. Additionally, vibrations or audiblealerts may also be issued by the application via the smartphone. In somecases, the application may be operable to communicate with a headset orearpiece (such as a Bluetooth headset for example) worn by the user tocommunicate audible alerts or warnings.

The sensors can detect various types of information such as chemicalcomponents of an environment, environmental conditions (e.g.,temperature, pressure, wind speed, wind direction, etc.), vibrationlevels, noise levels, biometric parameters (e.g., heart rate, bodytemperature, respiration rate, etc.), location (e.g., including2-dimensional and/or 3-dimensional position), and the like. The chemicalsensors can be detected using various types of gas sensors. The gasdetectors may include, but are not limited to, radiation detectors,smoke detectors, and detectors for determining abnormally low oxygencontent in the atmosphere, as well as a wide variety of detectors fordetecting chemically hazardous or flammable gases such as, for example,hydrogen sulfide, ammonia, carbon monoxide, natural gas, phosgene,organic compounds (e.g., volatile organic compounds, etc.), and soforth. The gas sensors can also be configured to include integratedwireless communications and the ability to periodically and under eventconditions, report the location information, time information, and gasconcentration level information wirelessly.

The use of multiple exposure values to determine a risk value may findapplications in several areas. In an embodiment, the multiple sensorinputs from the chemical sensors can be used to determine the presenceof an unmeasured chemical component. In an embodiment, one or more ofthe sensors may be targeted to a specific compound. However, chemicalsensors can also exhibit cross-sensitivity from other compounds presentin the environment. For example, hydrogen sulfide sensors can exhibit across-sensitivity reading from other chemicals such as carbon monoxide.For example, a carbon monoxide concentration of 10 ppm may produce a 1ppm response in a typical hydrogen sulfide sensor. The sensors aregenerally designed so that the cross-sensitivity to a non-detectedcompound is significantly less than the sensitivity to the compound thatthe sensor is designed to detect. In an embodiment, a ratio of a portionof the sensor output resulting from the target compound or compounds(e.g., a mixture such as an explosive gas mixture, etc.) to a portion ofthe sensor output resulting from an unmeasured and cross-interferingcompounds can be at least about 2:1, at least about 5:1, at least about10:1, at least about 100:1 or at least about 1,000:1. In someembodiments, the ratio of the portion of the sensor output resultingfrom the target compound or compounds to the portion of the sensoroutput resulting from an unmeasured and cross-interfering compounds canbe less than about 10,000:1 such that the cross-interference generates ameasureable portion of the signal that can be used to pattern match thepresence of any unmeasured compounds.

Each additional chemical in the environment may have an effect on thesensor readings, and the value of the cross-sensitivity for eachchemical may be unique to the sensor and the chemical component. Whenmultiple different chemical sensors are used, the cross-sensitivitypatterns may provide patterns that can give an indication of thepresence of an unmeasured chemical. For example, a multi-sensor arrayhaving a hydrogen sulfide sensor, a carbon monoxide sensor, and anammonia sensor may each provide a cross-sensitivity value for an unknowncompound. By detecting a potential cross-sensitivity pattern andmatching the pattern to a database of known patterns for the specificcompounds, one or more unknown compounds can be detected.

The cross-sensitivity patterns can be stored in the chemical patterndata store 122. The initial patterns can be determined in a number ofways. Since the cross-sensitivity is specific to the construction ofeach sensor, the sensors can he used individually or in groups to detectcross-sensitivity values for a plurality of chemicals. In an embodiment,the sensor or sensors can be exposed in controlled environments to knowngas concentrations, either to individual gases or mixtures having knowncomponent concentration values. For example, each of the sensors can beexposed to an organic compound such as benzene to determine thecross-sensitivity effects. In general, the relative cross-sensitivitybetween sensors may be used to identify the chemical, and the magnitudeof the cross-sensitivity may be used to determine the concentration ofthe chemical. The relative cross-sensitivity can be measured as ratiosof the cross-sensitivity of each sensor to each other sensor and/or asrelative percentages of sensitivity values. The resulting patterns fromthe initial data can be stored in the pattern data store 122. In someembodiments, the sensors can be exposed to combinations of chemicals todetermine the combined effects of various expected combinations ofunmeasured and/or measured chemicals in the case that thecross-sensitivity patterns do not have linear cross-sensitivity effects.For example, combinations of benzene, toluene, and xylene may be used todetermine the relative cross-sensitivity for a variety of sensor ifthese chemicals are expected to be present together in an environment.

The pattern information data in the pattern data store 122 can be usedbased on the measurements, or various types of learning algorithms canbe used to develop pattern models. For example, statistical models,neural networks (e.g., probabilistic neural networks, etc.), and thelike can be used to receive the patterns from the chemical testing andcreate a model for matching the patterns to specific chemicals andchemical concentrations. For example, the known patterns can serve astraining data to initially set up and establish the models andparameters used in the modes. The models may be used to extend theapplication of the patterns beyond those of the explicitly measuredcross-sensitivity values and/or used to interpolate thecross-sensitivity values for combinations of chemicals that are notexplicitly detected. The model, the model parameters, and various otherinformation used with such models can be stored in the pattern datastore 122 and used by the exposure application 112.

In some embodiments, the exposure application 112 can operate on thesafety communicator 150 in order to provide real time or near real timeinformation on the exposure values at the workers location. In thisembodiment, the patterns and/or model and parameters can be sent to thesafety communicator 150 at various intervals to allow the exposureapplication 112 to operate on the safety communicator 150. By having theexposure application 112 operate on the safety communicator 150, thedetected chemicals can be determined in real time or near real time evenif a network communication link is not present.

During use of the system 100, the chemical readings from each of the oneor more sensors 152, 154 can be received used by the safety communicator150 and/or the exposure application 112 on the data analytics server 102to determine the value of the measured chemicals. In addition, theexposure application 112 may detect a pattern of cross-sensitivity fromone or more additional chemicals based on the chemical sensor readings.The exposure application 112 may first determine the cross-sensitivityreadings for each chemical sensor. One or more aspects of thecross-sensitivity readings can be determined such as the relative valuesfor each sensor, the magnitude of each cross-sensitivity value, and thelike. The cross-sensitivity readings can then be compared to one or morepatterns to determine the identity of one or more unmeasured chemicalsthat may be present in the environment. In general, the pattern data caninclude the relative cross-sensitivity amongst particular sensors to oneor more chemicals. As described in more detail below, the patterns canalso include statistical model parameters or data to allow the patternsto be matched to one or more specific chemicals. The pattern data can beobtained from the pattern data store 122 and used to detect thepresence, and optionally, the concentration of one or more additionalchemicals in the environment. The presence of the one or more unmeasuredcompounds and the concentration of the compounds can be used in variousways.

In some embodiments, historical data from the historical data store 126can include measurements of chemicals at various locations in afacility. For example, gas samples can be measured at various locationsin a facility over time and analyzed using various techniques such asgas chromatography. The resulting analysis may provide an indication ofthe types of chemicals present at a given location. In otherembodiments, the process model may provide an indication of thechemicals present at various locations in a facility. Other informationsuch as environmental conditions (e.g., wind direction, wind speed,etc.) and the like can be used to provide a prediction of the types ofchemicals that can expected at various locations. This information canbe accessed by the exposure application to identity a list of one ormore chemicals that may be present at the location of the sensors 152,154. The list of expected chemicals can then be used as a starting pointfor analyzing the sensor readings to determine which chemicals from thelist may be present based on the cross-sensitivity of each chemical onthe list. The use of the historical and prediction data may improve theprediction of the unmeasured compounds by narrowing the total number ofsources and potential compounds present for the analysis of thecross-sensitivity values.

The exposure application 112 may output a list of one or more chemicalspresent in the environment. The list may include the detected chemicalsthat are directly measured by the sensors 152, 154. The list may alsoinclude one or more chemicals that are not directly measured (e.g., theunmeasured chemicals) based on the analysis of the cross-sensitivityvalues. The exposure application 112 can use the determined identity andconcentrations of the unmeasured chemicals in a number of ways. Forexample, the exposure application 112 may use the chemical identity andconcentrations to reduce or eliminate the cross-sensitivity values fromthe readings of the measured chemicals. For example, the detectedcross-sensitivity readings can be eliminated from the measured chemicalsto provide a inure accurate reading of the chemicals detected by thesensors. This may provide improved safety warnings as well as reducepotentially false alarms based on increased readings resulting fromcross-sensitivity. In this embodiment, the identity and concentration ofthe unmeasured compound can be determined and the cross-interference forthe identified compound can be calculated. The calculatedcross-interference can then be provided with the measurement from thesensor to provide a corrected output that accounts for the presence andcross-interference effects of the unmeasured compound. The determinationof the unmeasured chemicals and their concentrations can also be used toprovide exposure values for the workers, as described in more detailbelow.

In some embodiments, a learning algorithm may be used to update thepatterns in the pattern data store 122. Over time, and regardless ofwhere the exposure application executes, the sensor readings from thesensors 152, 154 can be stored in the sensor data store 124. In additionto the data from the sensors, the sensor data store 124 can includesensor readings for the facility from additional sensors or inputs suchas gas sampling data. In some embodiments, the same type of sensor maybe present at the facility as a stationary or portable sensor. Thesensor may have a different construction while sensing the sale type ofchemical and as a result provide a different cross-sensitivity readingfor the same type of unmeasured chemical. In this instance the sensordata may have different readings that can be used to improve thepattern. In some embodiments, specific sensors may measure compoundsthat are not detected by a multi sensor array. For example, a stationarysensor array may detect additional chemicals not detected by a portablesensor array. In this embodiment, the stationary sensor readings can beused to improve the patterns for the portable sensor arrays.

The exposure application 112 may periodically use the sensor data fromthe sensors 152, 154 in combination with the data from other sensors toperform an analysis of the sensor readings and chemicals present theenvironment to update the existing patterns and/or develop new patterns.The new patterns can include patterns for new chemicals that may bepresent and/or patterns for combinations of chemicals. In someembodiments, the updated analysis may be performed using data fromacross various facilities. For example, a sensor manufacturer maycollect sensor readings across multiple facilities and use the exposureapplication 112 to perform a pattern update. The resulting update canthen be sent to one or more facilities using the respective sensors. Theupdated analysis can be performed continuously, periodically, and/or atdiscrete times. Once received, the facilities can update the sensors andmodels used at the facility. This may allow data from one facility orlocation to be used in models and sensors at different facilities.

When the patterns are updated at a given facility and/or using data froma different facility or source, the updated patterns can be stored inthe pattern data store 122. When the exposure application 112 executeson a local device such as the safety communicator 150, the patterns canbe sent to the safety communicator 150 for performing thecross-sensitivity analysis. This may allow for an improved determinationof the presence and concentration of one or more chemicals that are notdirectly measured by a plurality of chemical sensors.

The exposure application 112 may provide a dynamic mapping of a facilityto determine if any areas have unacceptable exposure levels for anindividual for the measured and/or unmeasured chemicals. Using themapping, the exposure application 112 can determine the acceptablethresholds throughout an area. The acceptable exposure levels as well asalerts and notifications can be sent from the exposure application 112to the safety communicator 150 for display to each individual. In someembodiments, the acceptable threshold and/or mapping can be sent to thesafety communicator 150, which can perform the determination of thepresence of the unmeasured chemicals for the individual.

The exposure application 112 may proactively use the exposuredetermination for the measured and/or unmeasured chemicals in thefacility to suggest or require certain PPE for an individual. In someembodiments, the type of PPE being used by an individual can be storedin the personal protective equipment (PPE) data store 128 along withspecific information for various types of PPE. For example, the safetycommunicator 150 may be capable of detecting the presence of various PPEas well as compliance with the proper use of the PPE by the individualwithin the facility. PPE information for each of the PPE being used canbe obtained from the PPE data store 128 for use with the exposureapplication 112. For example, a type of respirator may be detected bythe safety communicator 150 including the proper positioning of therespirator as well as a model number or other identifier for therespirator. Using the identifier, the level and type of chemicalprotection can be retrieved from the PPE data store 128 and used in thedetermination of the individual exposure threshold.

This determination of the exposure level to the measured and/orunmeasured chemicals may be determined for each person present within afacility. The system 100 may continue to update the exposure values overtime to provide real time or near real time updates to the workers. Theupdated exposure levels can be checked against the current individual'slocation, PPE usage, training, and the like to determine if exposurelevel exceeds the applicable thresholds for the specific worker, if anythreshold is violated, a notification, alert, warning, or otherindication can be sent to the individual (e.g., to the safetycommunicator 150) and/or a manager or supervisor. The indication mayprovide updated requirements for working in the affected areas. Forexample, when it is determined that an unmeasured chemical exceeds theexposure threshold, a warning on the presence of the chemical as well asexposure level can be sent to the safety communicator. The warning caninclude a notification to use a different type of PPE. For example, arespirator capable of removing organic compounds may be required even iforganics are not expected in the area and are not directly measured.This may provide an improved detection and safety notification systemworkers at a facility.

Any of the systems and methods disclosed herein can be carried out on acomputer or other device comprising a processor, such as thecommunication device 150, the data analytics server 102, any of thesensors 152, 154, and/or the database 120 of FIG. 1. FIG. 2 illustratesa computer system 280 suitable for implementing one or more embodimentsdisclosed herein such as the acquisition device or any portion thereofThe computer system 280 includes a processor 282 (which may be referredto as a central processor unit or CPU) that is in communication withmemory devices including secondary storage 284, read only memory (ROM)286, random access memory (RAM) 288, input/output (I/O) devices 290, andnetwork connectivity devices 292. The processor 282 may be implementedas one or more CPU chips.

It is understood that by programming and/or loading executableinstructions onto the computer system 280, at least one of the CPU 282,the RAM 288, and the ROM 286 are changed, transforming the computersystem 280 in part into a particular machine or apparatus having thenovel functionality taught by the present disclosure. It is fundamentalto the electrical engineering and software engineering arts thatfunctionality that can be implemented by loading executable softwareinto a computer can be converted to a hardware implementation bywell-known design rules. Decisions between implementing a concept insoftware versus hardware typically hinge on considerations of stabilityof the design and numbers of units to be produced rather than any issuesinvolved in translating from the software domain to the hardware domain.Generally, a design that is still subject to frequent change may bepreferred to be implemented in software, because re-spinning a hardwareimplementation is more expensive than re-spinning a software design.Generally, a design that is stable that will be produced in large volumemay be preferred to be implemented in hardware, for example in anapplication specific integrated circuit (ASIC), because for largeproduction runs the hardware implementation may be less expensive thanthe software implementation. Often a design may be developed and testedin a software form and later transformed, by well-known design rules, toan equivalent hardware implementation in an application specificintegrated circuit that hardwires the instructions of the software. Inthe same manner as a machine controlled by a new ASIC is a particularmachine or apparatus, likewise a computer that has been programmedand/or loaded with executable instructions may be viewed as a particularmachine or apparatus.

Additionally, after the system 280 is turned on or booted, the CPU 282may execute a computer program or application. For example, the CPU 282may execute software or firmware stored in the ROM 286 or stored in theRAM 288. In some cases, on boot and/or when the application isinitiated, the CPU 282 may copy the application or portions of theapplication from the secondary storage 284 to the RAM 288 or to memoryspace within the CPU 282 itself, and the CPU 282 may then executeinstructions that the application is comprised of. In some cases, theCPU 282 may copy the application or portions of the application frommemory accessed via the network connectivity devices 292 or via the I/Odevices 290 to the RAM 288 or to memory space within the CPU 282, andthe CPU 282 may then execute instructions that the application iscomprised of. During execution, an application may load instructionsinto the CPU 282, for example load some of the instructions of theapplication into a cache of the CPU 282. In some contexts, anapplication that is executed may be said to configure the CPU 282 to dosomething, e.g., to configure the CPU 282 to perform the function orfunctions promoted by the subject application. When the CPU 282 isconfigured in this way by the application, the CPU 282 becomes aspecific purpose computer or a specific purpose machine.

The secondary storage 284 is typically comprised of one or more diskdrives or tape drives and is used for non-volatile storage of data andas an over-flow data storage device if RAM 288 is not large enough tohold all working data. Secondary storage 284 may be used to storeprograms which are loaded into RAM 288 when such programs are selectedfor execution. The ROM 286 is used to store instructions and perhapsdata which are read during program execution. ROM 286 is a non-volatilememory device which typically has a small memory capacity relative tothe larger memory capacity of secondary storage 284. The RAM 288 is usedto store volatile data and perhaps to store instructions. Access to bothROM 286 and RAM 288 is typically faster than to secondary storage 284.The secondary storage 284, the RAM 288, and/or the ROM 286 may bereferred to in some contexts as computer readable storage media and/ornon-transitory computer readable media.

I/O devices 290 may include printers, video monitors, liquid crystaldisplays (LCDs), touch screen displays, keyboards, keypads, switches,dials, mice, track balls, voice recognizers, card readers, paper tapereaders, or other well-known input devices.

The network connectivity devices 292 may take the form of moderns, modembanks, Ethernet cards, universal serial bus (USB) interface cards,serial interfaces, token ring cards, fiber distributed data interface(FDDI) cards, wireless local area network (WLAN) cards, radiotransceiver cards that promote radio communications using protocols suchas code division multiple access (CDMA), global system for mobilecommunications (GSM), long-term evolution (LTE), worldwideinteroperability for microwave access (WiMAX), near field communications(NFC), radio frequency identity (RFID), and/or other air interfaceprotocol radio transceiver cards, and other well-known network devices.These network connectivity devices 292 may enable the processor 282 tocommunicate with the Internet or one or more intranets. With such anetwork connection, it is contemplated that the processor 282 mightreceive information from the network, or might output information to thenetwork (e.g., to an event database) in the course of performing theabove-described method steps. Such information, which is oftenrepresented as a sequence of instructions to be executed using processor282, may be received from and outputted to the network, for example, inthe form of a computer data signal embodied in a carrier wave.

Such information, which may include data or instructions to be executedusing processor 282 for example, may be received from and outputted tothe network, for example, in the form of a computer data baseband signalor signal embodied in a carrier wave. The baseband signal or signalembedded in the carrier wave, or other types of signals currently usedor hereafter developed, may be generated according to several methodswell-known to one skilled in the art. The baseband signal and/or signalembedded in the carrier wave may be referred to in some contexts as atransitory signal.

The processor 282 executes instructions, codes, computer programs,scripts which it accesses from hard disk, floppy disk, optical disk(these various disk based systems may all be considered secondarystorage 284), flash drive, ROM 286, RAM 288, or the network connectivitydevices 292. While only one processor 282 is shown, multiple processorsmay be present. Thus, while instructions may be discussed as executed bya processor, the instructions may be executed simultaneously, serially,or otherwise executed by one or multiple processors. Instructions,codes, computer programs, scripts, and/or data that may be accessed fromthe secondary storage 284, for example, hard drives, floppy disks,optical disks, and/or other device, the ROM 286, and/or the RAM 288 maybe referred to in some contexts as non-transitory instructions and/ornon-transitory information.

In an embodiment, the computer system 280 may comprise two or morecomputers in communication with each other that collaborate to perform atask. For example, but not by way of limitation, an application may bepartitioned in such a way as to permit concurrent and/or parallelprocessing of the instructions of the application. Alternatively, thedata processed by the application may be partitioned in such a way as topermit concurrent and/or parallel processing of different portions of adata set by the two or more computers. In an embodiment, virtualizationsoftware may be employed by the computer system 280 to provide thefunctionality of a number of servers that is not directly bound to thenumber of computers in the computer system 280. For example,virtualization software may provide twenty virtual servers on fourphysical computers. In an embodiment, the functionality disclosed abovemay be provided by executing the application and/or applications in acloud computing environment. Cloud computing may comprise providingcomputing services via a network connection using dynamically scalablecomputing resources. Cloud computing may be supported, at least in part,by virtualization software. A cloud computing environment may beestablished by an enterprise and/or may be hired on an as-needed basisfrom a third party provider. Some cloud computing environments maycomprise cloud computing resources owned and operated by the enterpriseas well as cloud computing resources hired and/or leased from a thirdparty provider.

In an embodiment, some or all of the functionality disclosed above naybe provided as a computer program product. The computer program productmay comprise one or more computer readable storage medium havingcomputer usable program code embodied therein to implement thefunctionality disclosed above. The computer program product may comprisedata structures, executable instructions, and other computer usableprogram code. The computer program product may be embodied in removablecomputer storage media and/or non-removable computer storage media. Theremovable computer readable storage medium may comprise, withoutlimitation, a paper tape, a magnetic tape, magnetic disk, an opticaldisk, a solid state memory chip, for example analog magnetic tape,compact disk read only memory (CD-ROM) disks, floppy disks, jump drives,digital cards, multimedia cards, and others. The computer programproduct may be suitable for loading, by the computer system 280, atleast portions of the contents of the computer program product to thesecondary storage 284, to the ROM 286, to the RAM 288, and/or to othernon-volatile memory and volatile memory of the computer system 280. Theprocessor 282 may process the executable instructions and/or datastructures in part by directly accessing the computer program product,for example by reading from a CD-ROM disk inserted into a disk driveperipheral of the computer system 280. Alternatively, the processor 282may process the executable instructions and/or data structures byremotely accessing the computer program product, for example bydownloading the executable instructions and/or data structures from aremote server through the network connectivity devices 292. The computerprogram product may comprise instructions that promote the loadingand/or copying of data, data structures, files, and/or executableinstructions to the secondary storage 284, to the ROM 286, to the RAM288, and/or to other non-volatile memory and volatile memory of thecomputer system 280.

In some contexts, the secondary storage 284, the ROM 286, and the RAM288 may be referred to as a non-transitory computer readable medium or acomputer readable storage media. A dynamic RAM embodiment of the RAM288, likewise, may be referred to as a non-transitory computer readablemedium in that while the dynamic RAM receives electrical power and isoperated in accordance with its design, for example during a period oftime during Which the computer system 280 is turned on and operational,the dynamic RAM stores information that is written to it. Similarly, theprocessor 282 may comprise an internal RAM, an internal ROM, a cachememory, and/or other internal non-transitory storage blocks, sections,or components that may be referred to in some contexts as non-transitorycomputer readable media or computer readable storage media.

EXAMPLES

The disclosure having been generally described, the following examplesare given as particular embodiments of the disclosure and to demonstratethe practice and advantages thereof. It is understood that the examplesare given by way of illustration and are not intended to limit thespecification or the claims in any manner.

Example 1 Additional Gas Detection Without a Specific Sensor

A combination of sensors include a hydrogen sulfide (H₂S) sensor, asulfur dioxide (SO₂) sensor, and a nitrogen dioxide (NO₂) sensor areconsidered to for detecting chlorine gas (Cl₂). NO₂ can have a negativecross-sensitivity with H₂S and SO₂ sensors. The combination of all threesensors would allow for the measure of up to 3 gases simultaneously, andinfer at least the presence and concentration of a fourth component. Inthis example, when 10 ppm of Cl₂ gas is applied to the sensors, the NO₂sensor shows −10 ppm. When the gas mixture has 10 ppm Cl₂ and 10 ppmSO₂, then the NO₂ sensor shows −20 ppm, and the SO₂ sensor reads 10 ppm.The inferred chlorine concentration will be 10 ppm. Additionally, whenthe gas mixture has 10 ppm Cl₂, 10 ppm SO₂, and 50 ppm H₂S, the sensorswill read: H₂S is 50 ppm, SO₂ is 10 ppm, and NO2 −24 ppm. Based on thesereadings, the calculated Cl₂ concentration is 10 ppm. This informationis illustrated in Table 1.

TABLE 1 Additional Sensors reading gas Gas Concentration H₂S SO₂ NO₂detected single Cl₂ 10 ppm  0 ppm  0 ppm −10 ppm Cl₂ gas mix 2 Cl₂ 10ppm SO₂ 10 ppm  0 ppm 10 ppm −20 ppm Cl₂ mix 3 Cl₂ 10 ppm SO₂ 10 ppm H₂S50 ppm 50 ppm 10 ppm −24 ppm Cl₂

Thus, the presence of an unmeasured chemical is possible through the useof multiple chemical sensors, and the concentration can be determinedbased on the cross-sensitivity patterns.

Example 2 False Alarm and Reduction in Cross-Sensitivity Measurements

A combination of sensors include a hydrogen cyanide (HCN) sensor, ahydrogen sulfide (H₂S) sensor, and a sulfur dioxide (SO₂) sensor, areconsidered to for detecting a cross-sensitivity between compounds. WhenH₂S is present at a concentration of 5 ppm, the HCN sensor reading is 30ppm, which indicates a false alarm situation since no HCN is present.When H₂S is present at a concentration of 4 ppm and SO₂ is present at aconcentration of 5 ppm, the HCN sensor reading is 43 ppm, againindicating a false alarm. When H₂S is present at 3 ppm, SO₂ is presentat 5 ppm, and HCN is present at 10 ppm, the HCN sensor reading is 47ppm. The actual HCN concentration is just 10 ppm. This information isillustrated in Table 2.

TABLE 2 Sensors reading False Gas Concentration H2S SO2 HCN alarm singlegas H2S 5 ppm 5 ppm 0 ppm 30 ppm HCN mix 2 H2S 4 ppm SO2 5 ppm 4 ppm 5ppm 43 ppm HCN mix 3 H2S 3 ppm SO2 5 ppm HCN 10 ppm  3 ppm 5 ppm 47 ppmHCN* *real HCN concentration is 10 ppm

Thus, the cross-sensitivity patterns can be used to identify thepotential readings caused by the cross-sensitivity and detect an actualgas concentration in the surrounding gas. The cross-sensitivity can thenbe eliminated based on the patterns to avoid false alarms and present amore accurate measurement of the gases present.

Having described various systems and methods herein, a number ofembodiments can include, but are not limited to:

In a first embodiment, a method of determining the presence of anunmeasured chemical in an environment comprises receiving, by anexposure application stored in a non-transitory memory and executed on aprocessor, a plurality of sensor readings from a plurality of chemicalsensors, wherein each chemical sensor of the plurality of chemicalsensors is configured to detect a different chemical; determining, bythe exposure application, a cross-sensitivity pattern from one or moreunmeasured chemicals in the plurality of sensor readings; comparing, bythe exposure application, the cross-sensitivity pattern with one or moreknown chemical patterns; determining that the cross-sensitivity patternmatches at least one of the one or more known chemical patterns, whereinthe one or more known chemical patterns correspond to one or morechemicals; and identifying one or more unmeasured chemicals based ondetermining that the cross-sensitivity pattern matches the at least oneof the one or more known chemical patterns.

A second embodiment can include the method of the first embodiment,further comprising: determining a representation of thecross-sensitivity pattern; and determining a concentration of the one ormore unmeasured chemicals based on the representation of thecross-sensitivity pattern.

A third embodiment can include the method of the second embodiment,further comprising: determining a cross-sensitivity from the one or moreunmeasured chemicals and the concentration of the one or more unmeasuredchemicals; and removing the cross-sensitivity from the plurality ofsensor readings.

A fourth embodiment can include the method of any of the first to thirdembodiments, further comprising: determining a concentration of one ormore measured chemicals based on the plurality of sensor readings.

A fifth embodiment can include the method of any of the second to fourthembodiments, further comprising: comparing the concentration of the oneor more unmeasured chemicals to corresponding thresholds for the one ormore unmeasured chemicals; and providing an alert when the concentrationof at least one of the one or more unmeasured chemicals exceeds thecorresponding threshold.

A sixth embodiment can include the method of the first embodiment,further comprising: determining, by the exposure application, at leastone personal protective equipment requirement based on theidentification of the one or more unmeasured chemicals.

A seventh embodiment can include the method of any of the first to sixthembodiments, further comprising: determining an identification ofchemicals present in an area, wherein the one or more known chemicalpatterns include chemical patterns for the chemicals on theidentification of the chemicals.

An eighth embodiment can include the method of any of the first to sixthembodiments, further comprising: determining an identification ofchemicals present in an area, wherein the one or more known chemicalpatterns include chemical patterns only for the chemicals in theidentification of the chemicals.

A ninth embodiment can include the method of any of the first to eighthembodiments, further co sing: receiving, by the exposure applicationfrom one or more additional sensors, at least one measured value of theone or more unmeasured chemicals; correlating the at least one measuredvalue for the one or inure unmeasured chemicals with a determinedconcentration of the one or chore unmeasured chemicals; and updating theone or more known chemical patterns based on the correlating.

In a tenth embodiment, a chemical compound measurement system comprisesa memory storing an exposure application; a pattern store storing knownchemical patterns, and a processor, wherein exposure application, whenexecuted on the processor, configures the processor to: receive aplurality of sensor readings from a plurality of chemical sensors,wherein each chemical sensor of the plurality of chemical sensors isconfigured to detect a different chemical; determine a cross-sensitivitypattern from one or more unmeasured chemicals in the plurality of sensorreadings; compare the cross-sensitivity pattern with one or more of theknown chemical patterns; determine that the cross-sensitivity patternmatches at least one of the one or more known chemical patterns, whereinthe one or more known chemical patterns correspond to one or morechemicals; and identify one or more unmeasured chemicals based ondetermining that the cross-sensitivity pattern matches the at least oneof the one or more known chemical patterns.

An eleventh embodiment can include the system of the tenth embodiment,wherein the exposure application, when executed on the processor,further configures the processor to: determine a representation of thecross-sensitivity pattern; and determine a concentration of the one ormore unmeasured chemicals based on the representation of thecross-sensitivity pattern.

A twelfth embodiment can include the system of the eleventh embodimentwherein the exposure application, when executed on the processor,further configures the processor to: determine an expectedcross-sensitivity from the one or more unmeasured chemicals and theconcentration of the one or more unmeasured chemicals; and remove theexpected cross-sensitivity from the plurality of sensor readings.

A thirteenth embodiment can include the system of the eleventhembodiment, wherein the exposure application, when executed on theprocessor, further configures the processor to: compare theconcentration of the one or more unmeasured chemicals to correspondingthresholds for the one or more unmeasured chemicals; and provide analert when the concentration of at least one of the one or moreunmeasured chemicals exceeds the corresponding threshold.

A fourteenth embodiment care include the system of the tenth embodiment,wherein the exposure application, when executed on the processor,further configures the processor to: receive, from one or moreadditional sensors, at least one measured value of the one or moreunmeasured chemicals; correlate the at least one measured value for theone or more unmeasured chemicals with a determined concentration of theone or more unmeasured chemicals; and update the one or more knownchemical patterns based on the correlating.

A fifteenth embodiment can include the system of the tenth embodiment,wherein the exposure application, when executed on the processor,further configures the processor to: determine at least one personalprotective equipment requirement based on the identification of the oneor more unmeasured chemicals.

In a sixteenth embodiment, a method of determining, the presence of acompound in an environment comprises receiving a plurality of sensoroutputs from a plurality of chemical sensors, wherein each chemicalsensor of the plurality of chemical sensors is configured to detect adifferent chemical, wherein a ratio of a first portion of each of thesensor outputs resisting from a detected compound to a second portion ofthe sensor output resulting from an unmeasured compound is at leastabout 2:1; determining a cross-sensitivity pattern resulting from thepresence of the unmeasured compound using the plurality of sensoroutputs; comparing the cross-sensitivity pattern with one or more knownchemical patterns; determining that the cross-sensitivity patternmatches at least one of the one or more known chemical patterns, whereinthe one or more known chemical patterns correspond to one or morecompounds; and identifying the unmeasured compound based on determiningthat the cross-sensitivity pattern matches the at least one of the oneor more known chemical patterns.

A seventeenth embodiment can include the method of the sixteenthembodiment, further comprising: determining a representation of thecross-sensitivity pattern; and determining a concentration of theunmeasured compound based on the representation of the cross-sensitivitypattern.

An eighteenth embodiment can include the method of the seventeenthembodiment, further comprising: determining, for one or more of theplurality of chemical sensors, a cross-sensitivity from the unmeasuredcompound and the concentration of the unmeasured compound; and removingthe cross-sensitivity from one or more of the plurality of sensoroutputs.

A nineteenth embodiment can include the method of the seventeenthembodiment, further comprising: comparing the concentration of theunmeasured compound to a corresponding threshold for the unmeasuredcompound; and providing an alert when the concentration of theunmeasured compound exceeds the corresponding threshold.

A twentieth embodiment can include the method of the sixteenthembodiment, further comprising: receiving at least one measured value ofthe unmeasured compound; correlating the at least one measured value forthe unmeasured compound with a determined concentration of theunmeasured compound; and updating the one or more known chemicalpatterns based on the correlating.

While several embodiments have been provided in the present disclosure,it should be understood that the disclosed systems and methods may beembodied in many other specific forms without departing from the spiritor scope of the present disclosure. The present examples are to beconsidered as illustrative and not restrictive, and the intention is notto be limited to the details given herein. For example, the variouselements or components may be combined or integrated in another systemor certain features may be omitted or not implemented.

Also, techniques, systems, subsystems, and methods described andillustrated in the various embodiments as discrete or separate may becombined or integrated with other systems, modules, techniques, ormethods without departing from the scope of the present disclosure.Other items shown or discussed as directly coupled or communicating witheach other may be indirectly coupled or communicating through someinterface, device, or intermediate component, whether electrically,mechanically, or otherwise. Other examples of changes, substitutions,and alterations are ascertainable by one skilled in the art and could bemade without departing from the spirit and scope disclosed herein.

1.-15. (canceled)
 16. A method of determining presence of a chemical orcombination of chemicals in an environment, the method comprising:receiving, by an exposure application stored in a non-transitory memoryand executed on a processor, a plurality of sensor readings from aplurality of chemical sensors via a communication device associated withan individual, wherein each chemical sensor of the plurality of chemicalsensors is configured to detect a different chemical; determining, bythe exposure application, a cross-sensitivity pattern from the pluralityof sensor readings; comparing, by the exposure application, thecross-sensitivity pattern with one or more known chemical patterns, eachof the one or more known chemical patterns corresponding to a knownchemical or a known combination of chemicals; determining that thecross-sensitivity pattern matches one of the one or more known chemicalpatterns; identifying a chemical or combination of chemicals giving riseto the cross-sensitivity pattern based on determining that thecross-sensitivity pattern matches the one of the one or more knownchemical patterns; detecting, by the communication device, the presenceof a personal protective equipment and compliance with proper use of thepersonal protective equipment by the individual; determining, by theexposure application an exposure threshold level for the individualbased on the determined current type of personal protective equipment,the determined compliance with the proper positioning of the personalprotective equipment associated with the individual, and theidentification of the chemical or combination of chemicals giving riseto the cross-sensitivity pattern; monitoring, by the exposureapplication, an exposure value of the individual to the identifiedchemical or combination of chemicals giving rise to thecross-sensitivity pattern; and when it is determined that the exposurevalue exceeds the exposure threshold level for the individual, sendingto the communication device a warning on the presence of the chemical orcombination of chemical including a notification to use a particulartype of personal protective equipment.
 17. The method of claim 16,further comprising: determining a concentration of the chemical orcombination of chemicals based on the cross-sensitivity pattern.
 18. Themethod of claim 17, further comprising: determining a cross-sensitivitydue to the presence of the chemical or combination of chemicals givingrise to the cross-sensitivity pattern and the concentration of thechemical or combination of chemicals giving rise to thecross-sensitivity pattern; and removing the cross-sensitivity from theplurality of sensor readings.
 19. The method of claim 16, furthercomprising: determining a concentration of one of the chemicals based onthe sensor reading from the chemical sensor configured to detect saidone of the chemicals.
 20. The method of claim 16, further comprising:comparing a concentration of the chemical or combination of chemicalsgiving rise to the cross-sensitivity pattern to a correspondingthreshold for the chemical or combination of chemicals giving rise tothe cross-sensitivity pattern, wherein the corresponding threshold forthe chemical or combination of chemicals giving rise to thecross-sensitivity pattern is based at least in part on the determinedcurrent level of personal protective equipment associated with theindividual; and providing an alert when the concentration of thechemical or combination of chemicals giving rise to thecross-sensitivity pattern exceeds the corresponding threshold.
 21. Themethod of claim 16, further comprising: determining a list of chemicalsthat may be present at a location of the plurality of chemical sensors,wherein the one or more known chemical patterns include chemicalpatterns for the chemicals in the list.
 22. The method of claim 16,further comprising: determining a list of chemicals that may be presentat a location of the plurality of chemical sensors, wherein the one ormore known chemical patterns include chemical patterns only for thechemicals in the list.
 23. The method of claim 16, further comprising:determining, based on the cross-sensitivity pattern, a concentration ofthe chemical or combination of chemicals giving rise to thecross-sensitivity pattern; receiving, by the exposure application fromone or more additional sensors, at least one measured value of thechemical or combination of chemicals giving rise to thecross-sensitivity pattern; correlating the at least one measured valuefor the chemical or combination of chemicals giving rise to thecross-sensitivity pattern with the determined concentration of thechemical or combination of chemicals giving rise to thecross-sensitivity pattern; and updating the one or more known chemicalpatterns based on the correlating.
 24. The method of claim 16 furthercomprising, wherein the monitored exposure value of the individual isdetermined based on a current location of the individual and an expectedlocation of the individual.
 25. The method of claim 24, wherein theexpected location of the individual depends upon a predictive movementof the individual present in an area of the environment.
 26. The methodof claim 16 further comprising upon determining that the monitoredexposure value of the individual exceeds the exposure threshold value,determining a new personal protective equipment requirement for at leastone different type of personal protective equipment for the individual.27. The method of claim 26 further comprising sending a notification touse the at least one different type of personal protective equipment tothe communication device associated with the individual.
 28. The methodof claim 16, further comprising: receiving a current location of theindividual; receiving a current location associated with a secondindividual; determining an expected location of the second individualbased at least in part on the current location associated with thesecond individual and predicted movements associated with the secondindividual; determining a current type of personal protective equipmentassociated with the second individual; and determining, by the exposureapplication, in real time or near real time, at least one different typeof personal protective equipment associated with the second individualbased on the current location and the expected location of the secondindividual, the determined current type of personal protective equipmentassociated with the second individual, and the identification of thechemical or combination of chemicals giving rise to thecross-sensitivity pattern.
 29. The method of claim 16 further comprisingsending a notification of the at least one determined different type ofpersonal protective equipment associated with the second individual to acommunication device associated with the second individual.
 30. Themethod of claim 16, wherein determining, by the exposure application,the current type of personal protective equipment associated with theindividual comprises: detecting an identifier of the personal protectiveequipment associated with the individual; and based at least in part onthe identifier, retrieving the current type of personal protectiveequipment associated with the individual from a personal protectiveequipment datastore.
 31. A system comprising: a memory storing anexposure application; a pattern store storing known chemical patterns,each of the known chemical patterns corresponding to a known chemical ora known combination of chemicals, and a processor, wherein the exposureapplication, when executed on the processor, configures the processorto: receive a plurality of sensor readings from a plurality of chemicalsensors via a communication device associated with an individual,wherein each chemical sensor of the plurality of chemical sensors isconfigured to detect a different chemical; determine a cross-sensitivitypattern from the plurality of sensor readings; compare thecross-sensitivity pattern with one or more of the known chemicalpatterns; determine that the cross-sensitivity pattern matches one ofthe known chemical patterns; identify a chemical or combination ofchemicals giving rise to the cross-sensitivity pattern based ondetermining that the cross-sensitivity pattern matches the one of theknown chemical patterns; receive, from the communication device, adetection by the communication device of the presence of a personalprotective equipment by the individual and compliance with proper use ofthe personal protective equipment by the individual; determine, anexposure threshold level for the individual based on the determinedcurrent type of personal protective equipment, the determined compliancewith the proper positioning of the personal protective equipmentassociated with the individual, and the identification of the chemicalor combination of chemicals giving rise to the cross-sensitivitypattern; monitor an exposure value of the individual to the identifiedchemical or combination of chemicals giving rise to thecross-sensitivity pattern; and when it is determined that the exposurevalue exceeds the exposure threshold level for the individual, send tothe communication device a warning on the presence of the chemical orcombination of chemical including a notification to use a particulartype of personal protective equipment.
 32. The system of claim 31,wherein the exposure application, when executed on the processor,further configures the processor to: determine a concentration of thechemical or combination of chemicals giving rise to thecross-sensitivity pattern based on the cross-sensitivity pattern. 33.The system of claim 32, wherein the exposure application, when executedon the processor, further configures the processor to: determine across-sensitivity due to the presence of the chemical or combination ofchemicals giving rise to the cross-sensitivity pattern and theconcentration of the chemical or combination of chemicals giving rise tothe cross-sensitivity pattern; and remove the cross-sensitivity from theplurality of sensor readings.
 34. The system of claim 31, wherein theexposure application, when executed on the processor, further configuresthe processor to; compare a concentration of the chemical or combinationof chemicals giving rise to the cross-sensitivity pattern to acorresponding threshold for the chemical or combination of chemicalsgiving rise to the cross-sensitivity pattern; and provide an alert whenthe concentration of the chemical or combination of chemicals givingrise to the cross-sensitivity pattern exceeds the correspondingthreshold.
 35. The system of claim 31, wherein the exposure application,when executed on the processor, further configures the processor to:determine, based on the cross-sensitivity pattern, a concentration ofthe chemical or combination of chemicals giving rise to thecross-sensitivity pattern; receive, from one or more additional sensors,at least one measured value of the chemical or combination of chemicalsgiving rise to the cross-sensitivity pattern; correlate the at least onemeasured value for the chemical or combination of chemicals giving riseto the cross-sensitivity pattern with the determined concentration ofthe chemical or combination of chemicals giving rise to thecross-sensitivity pattern; and update the one or more known chemicalpatterns based on the correlating.